under drive pulley?

how well does a ud pulley work on a auto? should i put it on or just sell it?

put it on if you got it. i'll take it off your hands if you decide no to use 'em

What does an underdrive pulley do?

if u got one of the unorthadox ones, ill put a bid for it if u gettin rid of it

under drive pullies are smaller then regular stock pullies (alt, water pump, etc. where the belts are)

they are also lighter. if you think of a bicycle, the smaller the gear's are the more power you get, also for every pound you take off of the crank shaft you get something like 2 or 3 hp.